The present invention relates to mechanized sweeper trucks that utilize a primary broom to sweep debris from roadways and, more particularly, to method and apparatus for “leveling” the debris load within the debris container of such vehicles.
Mechanical broom sweepers are designed to pick-up debris not normally accepted by conventional regenerative or vacuum-type sweepers; this debris typically including asphalt nodules of varying size consequent to asphalt milling operations, rocks, stones, construction debris, broken masonry, and the like. In a typical design, as shown in schematic fashion in FIG. 1, a primary or main broom is rotated against the road surface to brush debris in the forward direction onto a mechanical elevator. The elevator typically includes a set of parallel flights that push the debris along an inclined floor pan to carry the debris upwardly for deposit through an entry opening of a debris collection bin or hopper. Because the density of the collected debris is relatively high, the debris drops from its point of entry and collects directly beneath its point of entry. As the debris pile accumulates and increases in elevation, the collected debris at the top of the pile tends to clog or block the entry opening, even though other parts of the collection hopper are comparatively unfilled.
In general, the problem cannot be solved by merely increasing or stepping up the operating speed of the elevator to more energetically throw the debris into the debris collection hopper. The sweeping vehicle and its main broom are best operated in speed ranges that assure the efficient sweeping of debris from the roadway and the efficient projecting of that swept debris into or onto the moving elevator. Thus, for any broom speed, the elevator speed is best maintained in a speed range that prevents a situation in which the elevator flights ‘overrun’ the brush function.
Vehicle operators have addressed this problem by abruptly applying the vehicle brakes to cause the debris pile to slump forwardly against the front wall of the debris container away from the entry opening on the rear wall of the debris collection hopper. This solution, while temporarily effective, tends to cause premature wear of the vehicle brakes and tires.